This invention relates to a living free radical polymerization process.
A process for producing low polydispersity polymers by free-radical chemistry using a living polymerization is disclosed in Macromolecules 1993, 26, 2987, by Georges et.al. However, this process utilizes monofunctional initiators and reports reaction times of 21 hours or more.
Another method of preparing low polydispersity vinyl aromatic polymers having accurate molecular weight control and block copolymer formation, giving rise to well-defined end groups, is disclosed in J. Am. Chem. Soc. 1994, 116, 11185-11186, by Hawker using a monofunctional nitroxyl initiator. However, long reaction times, e.g. 72 hours, are again required to reach a desirable conversion.
It would be highly desirable to utilize the control of the living free radical polymerization to produce high molecular weight vinyl aromatic polymers within shorter reaction times and produce block copolymers in a more efficient manner.